1. Field of the Invention
The present invention relates to a spray or injection device for spraying or injecting a product of interest in liquid form, making it possible to deliver at least a first dose and a second dose of said product in succession. The invention is especially applicable to a nasal spray making it possible to deliver two doses, one for each nostril.
2. Description of the Related Art
It is known to produce a nasal spray based on the general structure of a syringe, comprising detachable stop means. These stop means make it possible, when they are in place, to define a portion of travel of the plunger rod, in order to deliver a first dose, and may be withdrawn or removed in order to free the rest of the travel of the plunger rod, to allow the delivery of the second dose. U.S. Pat. Nos. 5,601,077 and 5,951,526, in the name of the Applicant, illustrate this technique.
U.S. Pat. No. 6,382,204, also in the name of the Applicant, also discloses the producing of a device comprising a casing receiving the syringe body and a pusher forming the plunger rod, the casing comprising lugs and the pusher comprising grooves in which these lugs can slide. Each groove comprises two longitudinal portions offset at an angle and an intermediate portion connecting these two longitudinal portions, perpendicular to the axis of the pusher. Each lug is able to slide in a first longitudinal portion until it comes into abutment against the pusher in the region for connecting this first longitudinal portion to the intermediate portion then, by axial rotation of the pusher, take the intermediate portion until it comes opposite the second longitudinal portion, and then slide in this second longitudinal portion. Said longitudinal portions thus define two successive portions of travel of the pusher, determining the delivery of the first and second doses of product, respectively.
The existing devices have the drawback of not being very easy to manipulate, whether in terms of removing said stop means according to the first technique cited or in terms of performing the relative pivoting of the pusher and of the casing according to the second technique cited.
These devices also have the drawback of not preventing errors in use.
Furthermore, the design of the aforementioned grooves and lugs is relatively complex to achieve in order to obtain good operational reliability.